Magnetic key and lock

ABSTRACT

A KEY AND PADLOCK COMBINATION COMPRISED OF A HOUSING, BOW, LOCKING MECHANISM AND MAGNETIZED KEY. THE LOCKING MECHANISM INCLUDES A CYLINDER RECEIVED WITHIN THE HOUSING AND A BOLT CARRIED BY THE CYLINDER FOR MOVEMENT INTO AND OUT OF LOCKING ENGAGEMENT WITH NOTCHES IN THE BOW. A PLURALITY OF ROTATABLE MAGNETIC TUMBLERS ARE CARRIED WITHIN THE CYLINDER TO NORMALLY HOLD THE BOLT IN THE LOCKED CONDITION.   WHEN THE KEY IS INSERTED INTO A KEYWAY IN THE CYLINDER, THE TUMBLERS ARE ROTATIONALLY ALIGNED BY THE MAGNETIC FIELD OF THE KEY IN SUCH A WAY AS TO PERMIT DISENGAGEMENT OF THE BOLT FROM THE BOW, THEREBY UNLOCKING THE PADLOCK.

. Jan.5,1971 Q 5 3,552,159

. MAGNETIC KEY AND LOCK Filed March '5, 1969 I NVENTOR.

(TL/WK f. ERA/6 W i M Arm/avers 3,552,159 Patented Jan. 5, 1971 3,552,159 MAGNETIC KEY AND LOCK Clark E. Craig, Modesto, Calif. (USS Wahkiakum County, FPO New York, N.Y. 09501) Filed Mar. 5, 1969, Ser. No. 804,394 Int. Cl. E05b 19/26, 47/00 US. Cl. 70-276 9 Claims ABSTRACT OF THE DISCLOSURE A key and padlock combination comprised of a housing, bow, locking mechanism and magnetized key. The locking mechanism includes a cylinder received within the housing and a bolt carried by the cylinder for movement into and out of locking engagement with notches in the bow. A plurality of rotatable magnetic tumblers are carried within the cylinder to normally hold the bolt in the locked condition.

When the key is inserted into a keywayin the cylinder, the tumblers are rotationally aligned by the magnetic field of the key in such a way as to permit disengagement of the bolt from the bow, thereby unlocking the padlock.

BACKGROUND OF THE INVENTION The present invention relates to key actuated locks and particularly to a lock employing a mechanism which is brought to an unlocked condition by the insertion of a magnetized key. The mechanism employs a series of tumblers which are rotationally brought into alignment with apertures in a template by the magnetic field of the key.

In the prior art, key actuated locking mechanisms which employ a series of tumblers are common. In the cylinder lock'variety, a cylinder is restrained against rotation of the cylinder. Although it is desired that only carried tumblers into corresponding recessions in the housing. A key mechanically aligns the tumblers in such a way as to remove their restraining influence upon the cylinder. The alignment of the tumblers of the typical cylinder lock is accomplished by inserting a key into a keyway extending axially into the cylinder. An irregular surface on the key changes the position of the tumblers to bring them into the desired alignment and thus to allow rotation of the cylinder. Although it is desired that only a key having a particular pattern of irregularities would accomplishthe tumbler alignment, mechanical manipulation of the tumblers by picks or other devices inserted into the keyway is often successfully practiced, thereby reducing the locks security.

The prior art also includes a class of electronic locks which employ a key having magnetic properties. Generally, the key has properties similar to a magnetic tape on which bits, or particular regions of independently oriented magnetism, are recorded. The lock comprises an electromagnetic sensing means to read the bits recorded on the key, electronic logic and electromotive means to elfect an unlocked condition when the proper recorded pattern is sensed. Such devices are both complex and expensive to manufacture and maintain, although they are less vulnerable to tampering than are their mechanical counterparts.

Finally, there are locks in the prior art which employ a magnetized key to attract or repel a keeper or tumblers. These devices typically depend only on a unique external configuration of the key to prevent opening the lock with any magnet. Because they are thus extremely susceptible to tampering, they are generally employed only where the need for security is minimal.

SUMMARY OF THE INVENTION The invention consists of a locking mechanism which may be used to lock a padlock bow, bolt works, or the like, and a magnetic key for use therewith. The basic element of the mechanism comprises a cylinder slidable within a hollow housing. Tumblers of generally cylindrical shape, each magnetized at a different point along 7 its longitudinal axis with an independently oriented magnetic field, are rotatably received and axially disposed within the cylinder. The ends of the tumblers are of noncylindrical configuration and protrude from one end of the cylinder toward a template having a plurality of noncylindrical apertures therein corresponding in cross section to the cross section of the tumblers ends. In the locked condition, the tumblers abut portions of the template and thus restrain movement of the cylinder toward the template.

The key comprises a rod adapted for insertion into a keyway formed along the axis of the cylinder. It is provided with independently oriented permanent magnetic fields at a plurality of points along its length, which fields are each disposed to independently interact with the field of each of the respective tumblers when fully inserted into the keyway. The interaction of the fields of the inserted key and those of the respective tumblers causes the tumblers to rotate into alignment with the apertures of the template, thereby permitting the cylinder to move toward the template to an unlocked position in which the tumblers are brought into mating relationship with the apertures therein.

The use of an independently oriented magnetic field on the respective tumblers prevents their simultaneous alignment by use of a single magnet, and the use of a magnetic field instead of a direct physical contact with the key to align the tumblers permits full enclosure of the tumblers. The latter characteristic prevents direct manual manipulation of the tumblers and, thereby, minimizes the possibility that a lock may be opened by physical tampering.

DESCRIPTION OF THE DRAWING DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In the drawing, the padlock is designated in its entirety by the numeral 10. It comprises, as its basic elements, a'hollow housing 12, a bow 14 and a locking mechanism 16. The legs of the how 14 are of unequal length and are receivable into two cavities 18 and 20 formed in and opening through the housing. The longer of the two legs, designated 22, is retained within the cavity 20 by a washer 24 and is adapted to swivel and to move inwardly and outwardly with respect to the cavity. The washer 24 is of slotted spring variety so that it may be snapped on to the leg 22 once it has been inserted into cavity 20. The bow 14 is in a closed position when the shorter leg, designated 26, is received in cavity 18. A compression spring 28 interposed between the blind end of cavity 20 and the leg 22 biases the bow 14 to move outwardly to an open position in which the leg 26 is removed from the cavity 18 and the washer 24 abuts a shoulder 30 formed in the interior of the cavity 20. Abutment of the washer 24 with the shoulder 30 prevents the bow 14 from being completely separated from the housing 12.

The interior of the housing 12 is formed with a bore 31 to slidably receive a cylinder 32. The cylinder 32 is constructed of a nonmagnetic material, such as nylon or aluminum, so as not to cause interference with the interaction of magnetic fields as described below. Ribs 34 extending outwardly from the cylinder 32 and located diametrically opposite each other are adapted to mate with corresponding grooves 36 in the housing 12. The grooves 36 open into the interior of the bore 31 and extend from the rear of the housing to a flange 37 on the front of the housing 12. This arrangement maintains the orientation of the cylinder 32 relative to the housing 12 and adapts the cylinder 32 for to and fro movement therein. A bolt 38 is carried within a passage 39 extending transversely through the cylinder 32. The bolt is formed in two segments with a spring interposed therebetween. To insert the cylinder 32 into the housing 12, the segments of the bolt 38 must be compressed into the passage 39 in the cylinder 32 until segments do not protrude beyond the surface of the cylinder 32. Once inside the housing 12, segments 38 expand outward into the cavities 18 and 20 in which the legs 22 and 26 of the bow 14 are receivable. The lock is in its locked condition, as shown in FIG. 2, when the bow is in the closed position and the bolt 38 is carried into locking engagement with notches 41 in the bow 14 by movement of the cylinder 32 into abutment with the flange 37.

A keyway 44 is formed along the axis of the cylinder 32 to provide for the insertion of key 48 into cylinder 32. A rib 50 on the key 48 and a groove 52 in the keyway 44 assure that the relative orientation of the key 48 and the cylinder 32 is the same each time the key 48 is inserted into the keyway 44.

Three longitudinally extending cavities 54 are formed in and open through the rear end of the cylinder 32. These cavities are disposed at annualarly spaced locations around the keyway 44 in substantially equally spaced relationship with respect thereto. Generally cylindrical tumblers 56 are rotatably received within the cavities and helical torsion springs 58 are interposed between the tumblers 56 and the cylinder 32 to bias the tumblers to a normal locking orientation. In the illustrated embodiment, a pas sage 57 (only one of which is illustrated) extends between each of the cavities 54 and the keyway 44 to provide an open magnetic flux path to the magnetized portion of the tumbler received in the cavity. This arrangement, as will become more apparent from the subsequent discussion, enhances the operation of the lock responsive to the insertion of the magnetic key employed therewith. Where it is desired to completely isolate the tumblers, however, these passages may be omitted.

The ends of the tumblers 56 protrude from the cylinder 32 and have portions 60 of triangular cross section formed thereon. A template 62 having corresponding triangular apertures 64 therethrough is disposed within the housing 12 immediately adjacent the portions 60. The apertures are proportioned to telescopically receive the portions 60 when aligned therewith and to provide abutment with the portions when misaligned. Ribs 66 on the template engage the grooves 36 to prevent rotation of the template relative to the housing 12. A compression spring 68 is interposed between template 62 and the cylinder 32 to normally bias the cylinder away from the template and against the flange 37, as seen in FIG. 3. A concavo-convex diaphragm 70 is received in circular groove 72 within the housing 12 and disposed adjacent template 62 to retain it within the housing 12 and to absorb any mechanical shock to which the mechanism 16 may be subjected. To the rear of the diaphragm 70, a cover 74 is swaged into place within the open end of the bore 31. In assembly, this cover is positioned after the mechanism 16 is in place within the housing 12.

From FIGS. 2 and 3, it can be seen that the portions 60 are normally misaligned with respect to the apertures 64 in the template 62. This condition is provided by the action of the torsion springs 58 and results in abutment of the portions 60 with the areas of the template 62 surrounding the apertures 64 when the cylinder 32 is forced towards the template. Such abutment, in turn, prevents the movement of cylinder 32 toward template 62 and, thus maintains the bolt 38 in locked engagement with notches 41.

By rotating the tumblers 56 to bring the portions 60 into alignment with respect to apertures 64 and applying a rearward pressure, the cylinder 32 may be slid rearward in housing 12, thus causing portions 60 to be introduced into apertures 64 and the disengagement of the bolt 38 from notches 41. Upon the latter occurrence, the spring 28 will force the bow 14 upward to the open position, thus disposing the lock 10 in an unlocked condition. If the cylinder is then released and the bow 14 is returned to its closed position, the spring 68 will once again force the cylinder 32 frontward to carry the bolt 38 into locked engagement with notches 41. Upon this occurrence the portions 60 will be disengaged from the apertures 64 and, assuming the tumblers 56 are free to rotate within the cavities 54, the springs 58 will return the tumblers to their normal orientation and the lock 10 will be in the locked condition.

A magnetic key 48 is used to align the portions 68 with the apertures 64. In FIG. 4, each tumbler 56 is shown to have a magnetic region associated therewith at a unique point along its axis. Thus the field of tumbler 56a is shown at one end thereof, that of tumbler 56b in the middle and that of 560 at the opposite end. Such localized magnetic regions may be accomplished in a variety of ways. One method would be to place a small permanent magnet into a nonmagnetic tumbler having a hollow interior. Another would be to form the tumblers by laminating layers of material, one of which would be magnetized. Whichever method is used, the field should be oriented so that when its axis 76 passes through the center of keyway 44, the portion 60 on that tumbler 56 is aligned with the corresponding aperture 64. In the simplified two dimensional diagram of FIG. 4, the tumblers field axes are in the plane of the drawing with either of the two magnetic poles directed toward the keyway 44 shown at the bottom.

The key 48 is constructed similarly to the tumblers 56 to exhibit three localized magnetic regions 48a, 48b and 480 corresponding to the axial location of the fields of the tumblers 56a, 56b and 560, respectively. The axes of these fields are colinear to those of the aligned tumblers 56 when the key 48 is fully inserted into the keyway 44. Thus, by inserting the key 48 into the keyway 44, the tumblers 56 rotate to align the axes 76 with those of the fields of the key 48 corresponding to the respective tumblers 56, as shown in FIG. 5B. FIG. 5A diagrammatically illustrates the normal misaligned condition of the axes when the key is removed from the lock. A north pole on the key 48 will attract the south pole on a turnbler 56 according to well-known magnetic behavior. With the tumblers 56 aligned by the key, inward pressure on the key 48 will force cylinder 32 rearward to unlock the padlock as hereinbefore described.

While the illustrated embodiment of the invention is shown and described as having torsion springs 58 disposed to normally bias the tumblers to the locking orientation, it is noted that the magnetic field of the key may be employed to perform this function. This results because the localized magnetic regions on the key would, naturally, bias the respective tumblers to locking orientation as the key is removed. Such magnetic orientation of the tumblers might even be enhanced by adding yet another distinct magnetic region to the distal end of the key beyond the region 48a for the sole purpose of moving the tumblers to a locking orientation as the key is removed. Such an additional region would be positioned so as not to interfere with movement of the tumblers to the unlocking orientation when the key is fully inserted. Where the magnetic influence of the key is employed to move the tumblers to the unlocking orientation, the springs 58 may be omitted in their entirety. In this case, suitable 2 bearings to support the tumblers for relatively tion would be provided.

It is intended that a mechanism 16 employing any number of magnetic tumblers be within the inventive concepts of this device. In this connection, it has been found useful to employ a modified four-sided key 48:: and keyway 44x, as shown in FIG. 6A, in conjunction with a four-tumbler mechanism, not shown, and a modified hexagonal key 48y and keyway 44y, as shown in FIG. 6B, in conjunction with a six-sided tumbler mechanism, not shown. No matter how many tumblers, the basic interaction between the key and tumblers which causes the tumblers to ,align with the apertures in the template remains the same. Furthermore, the cross-sections of portions 60 and apertures 64 are not required to be triangular. Any irregular shape may be used with equal success.

What is claimed is:

1. A lock mechanism for use in conjunction with a bolt works comprising, in combination:

(a) first and second members, at least one of which is disposed for movement relative to the other between a first position locking the works and a second position unlocking the works;

(b) a plurality of magnetic tumblers carried by the first member, said members each being disposed for independent rotation between a locking orientation and an unlocking orientation responsive to the imposition of a distinct magnetic field thereon;

(c) abutment means carried by the second member, said means being disposed for abutment with the tumblers when in locking orientation to prevent relative movement of the first and second members to the second position and to permit relative movement of the first and second members to the second position when the tumblers are in the unlocking orientation;

(d) keyway means having a predetermined relative to the tumblers;

(e) key means adapted for insertion into the keyway means, said means having a plurality of distinct mag netic fields associated therewith to cause the tumblers to rotate to the unlocking orientation upon insertion of the key means into the keyway means; and,

(f) biasing means disposed to rotationally urge at least one of the tumblers to the locking orientation upon removal of the key means from the keyway means.

2. A mechanism according to claim 1 further comprising a housing having a bore formed therein, and wherein:

(a) the first and second members are received within the bore and the first member is disposed for slidable movement therein between the first and second positions;

(b) a stop within the bore limits movement of the first free rotaorientation member away from the second member upon movement of the first member to the first position; and,

(c) the second member is restrained within the bore against substantial movement away from the first 5 member.

3. A lock mechanism according to claim 2, further comprising first resilient compression means interposed between the first and second members to normally urge the first member to the first position, said means being 0 deflectable to permit movement of the first member to the second position.

4. A lock mechanism according to claim 3 further comprising second resilient compression means interposed between the second member and the housing, said means being deflecta'ble to a limited degree to absorb shock upon forcing of the first member towards the second member when the tumblers are in locking orientation.

5. A mechanism according to claim 1, wherein:

(a) the abutment means comprises a surface on the 0 second member having a plurality of irregularly shaped apertures therein, one of which is disposed in alignment with each tumbler; and,

(b) the tumblers have irregularly shaped ends formed thereon and protruding from the first member toward the second member to abut portions of the surface when in the locking orientation and telescope into the apertures when in the locking orientation.

6. A mechanism according to claim 1 wherein each distinct field of the key means is disposed to influence but one tumbler upon insertion of the key means into the keyway means.

7. A mechanism according to claim 6 wherein:

(a) the keyway means comprises a generally rectilinear passage extending into and opening through the first member;

(b) the tumblers are generally rectilinear, disposed to rotate about axes substantially parallel to the passage, and each provided with a distinct confined magnetic field along a portion of the length thereof;

(c) the key means comprises an element of generally rectilinear configuration proportioned for insertion into the passage in a predetermined angular orientation relative thereto and the distinct magnetic fields associated therewith are positioned, respectively, to assume aligned opposition with the distinct magnetic fields of the tumblers upon such insertion.

8. A magnetic lock mechanism for use in conjunction with a bolt works, comprising in combination:

(a) a first member operatively associated with the bolt works for movement between a first position locking the works and a second position unlocking the works;

(b) a keyway formed in the first member;

(c) a plurality of magnetic tumblers received within the first member for rotation with respect thereto between a locking orientation and an unlocking orientation;

(d) biasing means interposed between the tumblers and the first member to bias the tumblers for rotation to the locked orientation;

(e) a second member disposed for abutment with the tumblers when in the locked orientation to prevent movement of the first member out of the first position and for release of the tumblers when in unlocking orientation to permit such movement;

(f) means to restrain the movement of the second member with respect to the bolt works; and,

(g) a key means adapted for insertion into the keyway,

said means having a plurality of mutually independent magnetic fields associated with distinct regions thereon to cause the tumblers to rotate to the unlocking orientation upon insertion thereof into the keyway.

9. A mechanism according to claim 8 wherein:

(a) the second member comprises a plate with a plurality of irregularly shaped apertures therein, one disposed in alignment with each tumbler; and,

(b) the tumblers have irregularly shaped ends formed thereon and protruding from the first member toward the second member to abut portions of the plate when in the locking orientation and telescope into the apertures when in the unlocking orientation.

References Cited UNITED STATES PATENTS 8 FOREIGN PATENTS 56,992 7/1967 Germany 70-276 1,543,981 9/1968 France 70276 5 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. 01. X.R. 

